Various methods for stably obtaining power from a battery pack are proposed.
Patent Document 1 (Japanese Unexamined Patent Publication No. 2003-217679) discloses the following discharge method. Whenever a battery voltage drops to a discharge termination voltage during discharge of a secondary battery, the secondary battery is intermittently discharged while repeating a temporary stop. In this case, when the discharge is restarted after a temporary stop, the discharge is performed while a current is reduced in a stepwise manner. Thereby, compared to a case where high-rate discharge is performed continuously, it is possible to extract a great deal of power from a secondary battery.